PHP实现MYSQL的查询功能

展示数据库

<?php
header("Content-Type: text/html;charset=utf-8");
$host = "127.0.0.1";
$port = "3306";
$user = "root";
$pass = "123654";
$charset = "utf8";  //设置默认字符
$link = mysql_connect("$host:$port",$user,$pass);  //链接数据库
$sql = "show databases";  //展示数据sql代码
if(!$result = mysql_query($sql,$link)){  //执行数据库代码
	echo "SQL执行失败"."<br>";
	echo "出错的地方是：".$sql."<br>";
	echo "错误代码是：",mysql_errno($this->link)."<br>";
	echo "错误信息是：",mysql_error($this->link)."<br>";
	die();
}
echo "<table>";
 //mysql_fetch_assoc()  从结果集中取得一行作为关联数组 
while($row = mysql_fetch_assoc($result)){
	// var_dump($row);
	echo "<tr>";
	echo "<td>"."<a href = "table.php?dbname=".$row["Database"]."">";
	//用的是字符串链接的方式 连接跳转的地方
	echo $row["Database"];  //输出数据库名
	echo "</a>"."</td>";
	echo "</tr>";
}
echo "</table>";

执行完sql语句之后返回的就是结果集；
实现结果如下：

<?php
header("Content-Type: text/html;charset=utf-8");
$host = "127.0.0.1";
$port = "3306";
$user = "root";
$pass = "123654";
$charset = "utf8";
$link = mysql_connect("$host:$port",$user,$pass);
mysql_query("set names ".$charset,$link);
$dbname = $_GET["dbname"];
$sql = "use `$dbname`";
mysql_query($sql,$link);
$sql = "show tables";  //展示表的sql语句
if(!$result = mysql_query($sql,$link)){
	echo "SQL执行失败"."<br>";
	echo "出错的地方是：".$sql."<br>";
	echo "错误代码是：",mysql_errno($this->link)."<br>";
	echo "错误信息是：",mysql_error($this->link)."<br>";
	die();
}
echo "<table>";
while($row = mysql_fetch_assoc($result)){
	 var_dump($row);
	echo "<tr>";
	echo "<td>";
	echo $row["Tables_in_".$dbname];
	echo "</td>";

	echo "<td>"."<a href = "column.php?tablename=".$row["Tables_in_".$dbname]."&dbname=".$dbname."">";
	echo "结构";
	echo "</a>"."</td>";

	echo "<td>"."<a href = "data.php?tablename=".$row["Tables_in_".$dbname]."&dbname=".$dbname."">";
	echo "数据";
	echo "</a>"."</td>";
	echo "</tr>";
}
echo "</table>";

展示表中的信息的时候，至少要传递两个参数，第一个是数据库的名字，第二个是表的名称 这样才能根据上面的两个信息找出表中的信息

<?php
header("Content-Type: text/html;charset=utf-8");
$host = "127.0.0.1";
$port = "3306";
$user = "root";
$pass = "123654";
$charset = "utf8";
$link = mysql_connect("$host:$port",$user,$pass);
mysql_query("set names ".$charset,$link);
$dbname = $_GET["dbname"];
$tablename = $_GET["tablename"];
$sql = "desc `$dbname`.`$tablename`";  //展示出表的信息
if(!$result = mysql_query($sql,$link)){
	echo "SQL执行失败"."<br>";
	echo "出错的地方是：".$sql."<br>";
	echo "错误代码是：",mysql_errno($this->link)."<br>";
	echo "错误信息是：",mysql_error($this->link)."<br>";
	die();
}
echo "<table>";
while($row = mysql_fetch_assoc($result)){
	 //var_dump($row);
	echo "<tr>";
	echo "<td>";
	echo $row["Field"];  //输出名称
	echo "</td>";

	echo "<td>";
	echo $row["Type"];  //输出类型
	echo "</td>";
	echo "</tr>";
}
echo "</table>";

<?php
header("Content-Type: text/html;charset=utf-8");
$host = "127.0.0.1";
$port = "3306";
$user = "root";
$pass = "123654";
$charset = "utf8";
$link = mysql_connect("$host:$port",$user,$pass);
mysql_query("set names ".$charset,$link);

$dbname = $_GET["dbname"];//获得数据库名
$tablename = $_GET["tablename"];//获得表名

//选择某认数据库
$sql = "use `$dbname`";
if(!$result = mysql_query($sql,$link)){
	echo "SQL执行失败"."<br>";
	echo "出错的地方是：".$sql."<br>";
	echo "错误代码是：",mysql_errno($this->link)."<br>";
	echo "错误信息是：",mysql_error($this->link)."<br>";
	die();
}
//获得字段信息
$sql = "desc `$tablename`";
if(!$result = mysql_query($sql,$link)){
	echo "SQL执行失败"."<br>";
	echo "出错的地方是：".$sql."<br>";
	echo "错误代码是：",mysql_errno($this->link)."<br>";
	echo "错误信息是：",mysql_error($this->link)."<br>";
	die();
}

echo "<table border="1">";
//展示字段
echo "<tr>";
while($rows = mysql_fetch_assoc($result)){
	echo "<th>";
	echo $rows["Field"];
	echo "</th>";
}
echo "</tr>";
//查询每个表的数据
$sql = "select * from `$tablename` where 1";
if(!$result = mysql_query($sql,$link)){
	echo "SQL执行失败"."<br>";
	echo "出错的地方是：".$sql."<br>";
	echo "错误代码是：",mysql_errno($this->link)."<br>";
	echo "错误信息是：",mysql_error($this->link)."<br>";
	die();
}

//遍历结果集 得到所有字段
while($rows = mysql_fetch_assoc($result)){
	echo "<tr>";
	foreach ($rows as $value) {
		echo "<td>";
		echo $value === "" ?" ":($value===NULL?"NULL":$value);
		//三目运算符的嵌套
		echo "</td>";
	}
	echo "</tr>";
}
echo "</table>";